Subjects: 120 adult male, patients referred of outpatient colonoscopy will be the study subjects and controls. We do 15-18 colonoscopies a day and assuming half that number meet criteria for inclusion and consent to the study we will be able to recruit 120 patients in 6 months or less. Our records indicate more than 1000 colonoscopies are performed in a six-month period. If we conservatively estimate 10% ineligible patients > (n=900 remaining), 50% refusal (n=450 remaining), and enrollment on 4 of 5 weekdays (n=360 remaining), the six-month period would provide adequate sample size. The study would end if the target sample size is reached early.